peroral

Peroral, from the Latin per os, denotes administration of substances through the mouth. In medical usage, it describes delivering a drug or nutrient by swallowing so that it enters the gastrointestinal tract. It is commonly equated with oral administration, though the term peroral emphasizes the route itself rather than the location of administration.

Peroral administration is the most common and convenient route for systemic therapy, as it is noninvasive and suitable for self administration. The substance is absorbed as it passes through the digestive system, with primary absorption in the small intestine and some uptake in the stomach. Absorption is influenced by gastric pH, food intake, gastric emptying, intestinal transit, and interactions with other substances.

Many drugs taken perorally undergo hepatic first-pass metabolism, which can markedly reduce peak concentration in the bloodstream and create variability in bioavailability among patients. Formulations include tablets, capsules, liquids, and suspensions. The oral route offers advantages such as convenience and lower cost, but it also yields slower onset, variable absorption, and potential degradation by stomach acid or gut enzymes.

Limitations and considerations: peroral therapy may be unsuitable for patients with vomiting, severe dysphagia, or risk of aspiration; some medications require modified-release designs or alternative routes to achieve reliable effect. Drug interactions with food or other medicines can alter absorption. In procedural contexts, the adjective peroral may describe approaches through the mouth, as in peroral endoscopy.

See also: oral administration, per os, enteral route, peroral endoscopy.